Jonathan Dixon

Conciliatory views of peer disagreement (aka Conciliationism) have repeatedly been challenged on the grounds that they are epistemically self-undermining. Recently, Dixon (2024) argues that this challenge is worse than previously thought: it is (almost certainly) permanent and this provides strong reason to abandon Conciliationism as (almost certainly) hopeless. In response, Justin (2025, Episteme) argues that the self-undermining challenge and Dixon’s arguments, at best, only apply to the belief-suspension versions of Conciliationism but not to degree-of-belief (aka credal) versions of Conciliationism. Thus, not only can Conciliationists largely avoid the self-undermining challenge but, contra Dixon, this challenge also does not provide adequate reason to abandon Conciliationism as hopeless. This paper argues that not only can the self-undermining challenge be reformulated to apply to credal versions of Conciliationism, this reformulated challenge extends and further supports Dixon’s pessimism: because there (almost certainly) is or will be peer disagreement on any way of responding to this reformulated challenge, any response (almost certainly) be defeated by the very view it is attempting to defend. Thus, credal Conciliationism is also (almost certainly) permanently self-undermining and there is (almost certainly) still no hope for Conciliationism.

[For a Symposium on Kevin McCain’s _Explanatory Solutions to Skeptical Problems_. Please cite published version.] In Explanatory Solutions to Skeptical Problems (OUP, 2025), McCain aims to show that his preferred view of justification, which he motivates and defends in previous work (Appearance & Explanation (OUP, 2021)), can be used to adequately respond to a host of skeptical problems. I will focus on evaluating how effective McCain’s account of justification is in responding to one kind of skepticism: Cartesian external world skepticism. I argue that McCain’s response either fails or needs more argumentation to be convincing. While I disagree with much of McCain’s way of responding to the arguments for Cartesian skepticism, I can recommend this book to anyone who is interested in skepticism, explanatory inference, and – more generally – good philosophy books.

Using two decades worth of experimental philosophy (aka x-phi), Edouard Machery argues in Philosophy within its Proper Bounds (OUP, 2017) that philosophers’ use of the “method of cases” is unreliable because it has a strong tendency to elicit different intuitive responses from non-philosophers. And because, as Machery argues, appealing to such cases is usually the only way for philosophers to acquire the kind of knowledge they seek, an extensive philosophical skepticism follows. I argue that Machery’s “Unreliability” argument fails because, once its premises are percisified, they are either self-defeating or without justification. This is a significant result because Machery’s arguments are the most widely cited and discussed x-phi arguments for philosophical skepticism and many hold that Machery provides the most empirically informed, convincing, and thus best case for this kind of skepticism. So, if my arguments are sound, then the best x-phi argument for philosophical skepticism fails. I further argue that this result provides strong reason to believe the more general conclusion that “negative” x-phi is likely doomed: x-phi likely can never support a substantive philosophical skepticism. Ultimately, I argue for the broad conclusion that all empirically minded arguments for philosophical skepticism are likely to fail for the same reasons that Machery’s does, i.e. they are (likely) self-defeating.

Conciliationism is the family of views that rationality requires agents to reduce confidence or suspend belief in p when acknowledged epistemic peers (i.e. agents who are (approximately) equally well-informed and intellectually capable) disagree about p. While Conciliationism is prima facie plausible, some have argued that Conciliationism is not an adequate theory of peer disagreement because it is self-undermining. Responses to this challenge can be put into two mutually exclusive and exhaustive groups: the Solution Responses which deny Conciliationism is self-undermining and attempt to provide arguments which demonstrate this; and the Skeptical Responses which accept that Conciliationism is self-undermining but attempt to mitigate this result by arguing this is either impermanent and/or not very worrisome. I argue that, by Conciliationism’s own lights, both kinds of responses (almost certainly) fail to save Conciliationism from being self-undermining. Thus, Conciliationism is (almost certainly) permanently self-undermining. This result is significant because it demonstrates that Conciliationism is likely hopeless: there is likely nothing that can save Conciliationism from this challenge. I further argue that Conciliationism, like any view, should be abandoned if it is (almost certainly) hopeless.

Recently John Turri [-@turri:2015e] has argued, contra the orthodoxy amongst epistemologists, that reliability is not a necessary condition for knowledge. From this result, Turri [-@turri:2015f; -@turri:2017d; -@turri:2016; -@turri:2019] defends a new account of knowledge—called abilism—that allows for unreliable knowledge. I argue that Turri’s arguments fail to establish that unreliable knowledge is possible and argue that Turri’s account of knowledge is false because reliability must be a necessary condition for knowledge.

The Cartesian arguments for external world skepticism are usually considered to be significant for at least two reasons: they seem to present genuine paradoxes and that providing an adequate response to these arguments would reveal something epistemically important about knowledge, justification, and/or our epistemic position to the world. Using only premises and reasoning the skeptic accepts, I will show that the most common Cartesian argument for external world skepticism leads to a previously unrecognized self-undermining dilemma: it either leads to a reductio ad absurdum, or to avoid this reductio the skeptic must accept that this argument is epistemically idle—it does not provide any support for external world skepticism. Either way, this Cartesian argument cannot legitimately threaten or even call into question our beliefs about the external world. And thus, either way, this Cartesian argument for external world skepticism is not epistemically significant—it is not a genuine paradox and adequately responding to it need not reveal anything epistemically important.

This dissertation concerns whether philosophy as a discipline can, and does, produce philosophical knowledge. Specifically, this dissertation concerns several prominent arguments for philosophical skepticism. Some support philosophical skepticism by arguing that the philosophical practice of appealing to intuitions to justify philosophical beliefs is illegitimate because either intuitions are not a legitimate kind of evidence or intuitions are an unreliable source of justification. Others argue that philosophical knowledge is untenable because philosophers rarely, if ever, resolve their philosophical disagreements despite spending their professional lives attempting to do so. In brief, the purpose of this dissertation is to defend philosophical knowledge from these arguments by showing that philosophical knowledge is not threatened by either intuition or disagreement skepticism.

While many have argued that moral disagreement poses a challenge to moral knowledge, the precise nature of this challenge is controversial. Indeed, in the moral epistemology literature, there are many different versions of ‘the’ argument from moral disagreement to moral scepticism. This paper contributes to this vast literature on moral disagreement by arguing for two theses: 1. All (or nearly all) moral disagreement arguments share an underlying structure; and, 2. All moral disagreement arguments that satisfy this underlying structure cannot establish moral scepticism because this underlying structure leads to a previously unrecognized reductio ad absurdum. In short, I argue that this reductio argument (very likely) refutes all versions of the moral disagreement to moral scepticism argument in one fell swoop.